1. Field of the Invention
The present invention relates to an airflow guiding structure for a heat-dissipating fan.
2. Description of Related Art
FIG. 1 of the drawings illustrates a typical heat-dissipating fan including a casing 10, an air inlet 11 defined in a side of the casing 10, an air outlet 12 defined in the other side of the casing 10, a base 13, and a plurality of ribs 14. The base 13 is secured by the ribs 14 in the air outlet 12. A stator (not shown) and an impeller (not shown) are mounted to the base 13. When the impeller turns, air is sucked into the casing 10 via the air inlet 11 and exits the casing 10 via the air outlet 12 to dissipate heat from an object such as a fin or a central processing unit.
Although the above-mentioned heat-dissipating fan provides a certain heat-dissipating effect, the heat-dissipating operation can only be performed on an object directly below the air outlet 12, as the airflow can only flow along an axial direction of the air outlet 12. In a case that the object is not located directly below the air outlet 12, the airflow cannot flow through the object in a uniform manner, resulting in non-uniform heat dissipation and poor heat-dissipating effect. On the other hand, since the object is generally mounted in a limited space such as in a notebook type computer (or a laptop  computer) in a position not directly below the base 13 or outside the area of air outlet, the heat-dissipating effect is adversely affected. The heat-dissipating effect is also adversely affected if the object is too large to be completely within an area directly below the heat-dissipating fan. Further, turbulence tends to occur when the airflow is passing through the ribs 14. Noise is thus generated while having a lower heat-dissipating effect.